1. Field of the Invention
The present invention generally relates to devices which separate particulates from flowing fluids, and more specifically to vacuum cleaners which use centrifugal force for particle separation, such as cyclonic or vortex vacuum cleaners.
2. Background Information
There are a large number of designs of vacuum cleaners, but two basic styles are prominent. One of these styles is a vacuum which utilizes a bag to collect filtered dirt. The bag serves as the filter and accumulates dust until full, at which time it is emptied. A stream of air is drawn into the bag, and pores in the bag wall stop particles which are in the air, but allow air to exit the bag. A problem with vacuums which utilize bags, is that the bag must be somewhat porous in order to allow the passage of a large flow of air. Bags which are fairly porous can also allow the passage of a large volume of particulates. As much as 40% of the dust can pass through such a bag and reenter the house, suspended in air currents, until it settles out.
As soon as the vacuum cleaner begins to accumulate dust, the pores of the bag begin to be blocked, and the air flow decreases. As the air flow decreases, the vacuum cleaner floor tool can pass over particles, and the air flow may not be enough to lift them off the surface and into the vacuum cleaner. As the bag fills with particles, the volume of air flow becomes less and less, and the filtration power of the vacuum bag becomes more and more, until the filtration efficiency is so high that not even air can exit the bag. Another disadvantage of bag systems is the expense and messiness of a bag. When a bag is full of dirt, the vacuum cleaner must be opened and the bag removed and replaced with a new one. If large numbers of bags are used, the expense of new bags is undesirable.
Still another problem with vacuums which use a bag is that users will try to continue using the vacuum as long as there is space in the bag to hold more dirt. However, a bag may be totally used up by filtering a small amount fine dust particles. These fine powders can completely block every pore in the filter bag, and reduce the air flow through the filter bag to zero. A user may be dissatisfied with the vacuum when he opens the filter and finds that it is not full of dirt, but merely has a small amount of dirt on the inside of the bag. Some users may continue trying to use a vacuum in such a state, either not understanding that the usefulness of the bag has ended, or trying to conserve money by getting the most life out of every bag.
A second type of vacuum cleaner uses cyclonic separation of particulates from the air. The typical cyclonic vacuum cleaner is configured so that a stream of air enters a vacuum chamber at a tangent to the cylindrical wall of the vacuum chamber. The air circulates around the wall of the container, with the heavier particles moving adjacent to the wall or bouncing against the wall, and the swirling air in the center of the chamber being more free of particulate matter. An air intake tube to the motor and fan is typically located at the bottom of the canister and runs vertically through the center of the canister, so that the cleaner central air is drawn into the central intake tube, and is drawn back towards the top of the container, where it may exit the vacuum cleaner. In many cyclonic designs, a supplemental filter is also placed so that air is filtered through a particulate filter before exiting the vacuum cleaner.
Examples of cyclonic vacuum cleaners include that described in U.S. Pat. No. 5,080,697, to Fink.
Another type of cyclonic vacuum cleaner is shown in U.S. Pat. No. 6,026,540 to Wright et al. In Wright, as shown in FIG. 4, air enters the vacuum chamber at J and circulates spirally around the dirt cup 52. Dirt accumulates in the bottom of the dirt cup as the heavier particulates fall out of the air stream. A main filter element K is situated in the center of the cyclonic air flow chamber 54, and the cleaner air from the center of the spiraling air stream enters the main filter element K, and is drawn by a vacuum motor into an exhaust channel 60. As can be seen, the cyclonic effect serves to keep heavier particles out of the filter element K. However, it is the fine particles which will occlude the filter and stop air flow, and the filter can be clogged and ineffective long before the dust cup 52 is full.
One type of cyclonic vacuum cleaner is that sold by Hoover as the Vortex model. In the Hoover vacuum cleaner, air enters a cyclonic chamber tangentially, and spins around the side of the cylindrical chamber. Heavier particles fall to the bottom of this chamber and out of the main air flow. Air is drawn from the center of this cylindrical chamber and passes to a second stage centrifugal separating chamber which is stacked on top of the first stage. Particles which travel around the outside circumference of the second cylindrical chamber are again separated from the main air stream, and air from the center of the chamber goes into a third centrifugal or cyclonic separation chamber. This chamber is also stacked on top of the previous chamber, and further separates particles from air in the center of the chamber.
Another example of prior art cyclonic vacuums is a vacuum made by Eureka, and sold as the True HEPA Model. This vacuum cleaner is an upright, with a clear chamber in the center of the upright portion of the vacuum. Visible inside the clear chamber is what appears to be a funnel on the right, and a collection chamber in the left side. The funnel is actually a cyclonic chamber, in which air enters at a tangent and spins around the funnel, finally exiting at the bottom of the funnel. As the air enters the funnel, it is spinning, and large particles that are suspended in the air are expelled from the air stream before they enter the funnel. The large particles enter a chamber off to one side of the funnel which collects these large particles. The particles which are not separated in this initial separation chamber continue on through the funnel, and eventually encounter a filter which filters particulates before the air stream enters the fan. The Eureka vacuum is typical of a large number of cyclonic vacuums, in which a centrifugal or cyclonic chamber is used as a prefilter, to separate larger particles from the air stream, and a pleated paper or fibrous filter is utilized to filter the fine particles out of the air stream. The Phantom is another example of this type of filtration.
It is an object of the invention to provide a bagless particle separator based on cyclonic separation of particles. It is a further object to provide a high efficiency separation device which separates particles from moving fluid, and sorts the particles according to size. It is a further object to provide a vacuum cleaner which operates without bags, and which efficiently separates particles from air.
These and other objects are achieved by a vortex particle separator. The vortex particle separator is a highly effective particle separator for use in a vacuum cleaner. It is also useful in any situation in which particles need to be removed from a fluid flow. This can include use as a room air purifier, to remove smoke particles, pollen and dust from the room air. It is also effective at separating particles from air in industrial situations, such as in a smoke stack, either as a prefilter for a bag house, or as a replacement for bag filters. This vortex separator can also be used to sort materials by size.
The vortex particle separator utilizes a cyclonic chamber which is an auger or spiral ramp, confined within a cylindrical tube. Air is drawn through this cyclonic chamber, and particles which move to the periphery of the cyclonic chamber exit the cyclonic chamber by centrifugal force, and are captured in a collection chamber.
In its simplest format, the vortex particle separator utilizes a single stage for separation of particles. In this version of the vortex particle separator, a housing encloses the cyclonic chamber. The housing has an intake port and an exhaust port, and the housing may be closed at top and bottom, forming an enclosed chamber. The housing can be a rigid chamber, such as a plastic or metal chamber, and it can also be made of a flexible material, such as paper, fabric or plastic. The housing of the vortex particle separator can be porous or non-porous. If porous it would typically be a paper, fabric, and or a fabric bag. The housing may include a mechanism for opening and closing the top and bottom end of the housing.
Within the housing is located an auger or spiral ramp. The spiral ramp is enclosed by a cylindrical tube, called the core shroud. The spiral ramp enclosed within the cylindrical core shroud forms the cyclonic chamber. The spiral ramp has an inside edge and an outside edge, with the outside edge adjacent to the inside edge cylindrical core shroud, and sealed against the core shroud. The cylindrical core shroud has an interior surface and an exterior surface, and encloses the spiral ramp or auger. The core shroud and the spiral ramp form a pathway for air through the housing, and confine the air to the spiral pathway of the cyclonic chamber.
The cyclonic chamber includes a means of excluding particulates from the cyclonic chamber. This can include a means of keeping particulates from entering the cyclonic chamber, or a means of expelling the particulates after they have entered the cyclonic chamber, or both. The cyclonic chamber can terminate before it connects to the intake port of the housing, so that there is space between the beginning of the cyclonic chamber and the inlet of the housing. This space forms a gap or debris opening and allows the passage of large particulates out of the air flow and into the housing. The cyclonic chamber attaches to an air outlet of the housing, through which air exits the cyclonic chamber and the housing. A suction creating means is included, and is typically a motor with a fan. The fan propels air through the cyclonic chamber and through the housing. A means of connecting the fan and motor to the housing is also included, such as by direct attachment to the motor shaft, or by belt, chain, or gear connection.
If the cyclonic chamber is spaced apart from the air inlet of the housing, then the air propulsion means is mounted adjacent to the air outlet of the housing. When the air propulsion means, typically a fan and motor, is activated, a stream of air races through the cyclonic chamber, and forms a vortex of air beyond the inlet to the cyclonic chamber and extending into the air inlet of the housing. As air and particulates enter this vortex, the air assumes a spiraling pathway as it passes through the air inlet. Since there is a gap between the air inlet and the inlet to the cyclonic chamber, the heavier particles are thrown outside the cyclonic chamber and into the housing, and the air which enters the cyclonic chamber is free of these particulates.
A particulate filter may optionally be mounted between the air outlet of the housing and the fan.
A means is provided in the vortex particle separator to remove the accumulated particulate debris from the air chamber formed between the housing and the core shroud. The means of removing the particulates can be by removing the bottom of the housing, by removing the top of the housing, by having the housing split open in a clam shell fashion, or any other means which is typically used in the industry. If the housing is a flexible material, it can be disposed of with the dirt enclosed. The top of the housing would typically be an attached plate which includes the air inlet for the housing. A vacuum hose would typically be attached to the air inlet, and would extend to a floor tool or other intake or cleaning tool. The bottom of the housing may be removable, and may serve as a means of debris removal. In some configurations of the vortex particle separator, the air propulsion means could be mounted outside of the housing at the air inlet, and would push air through the cyclonic chamber.
In another version, the air propulsion means is mounted outside the housing and adjacent to the air outlet, and pulls air through the cyclonic chamber. The vortex particle separator can be configured to include a particulate filter in the air stream which exits the cyclonic chamber. The vortex particle separator can also be configured so that air speed is increased in the cyclonic chamber due to the spiral ramp and the cyclonic chamber decreasing in radius. This would cause air to move faster around the smaller radius, which would aid in separating smaller particulates. The air speed can increase through the cyclonic chamber by a change in pitch of the spiral ramp also. The vortex particle separator can also be configured so that air speed increases through the cyclonic chamber by the inner core of the cyclonic chamber increasing in diameter, so that there is less volume for air in the spiral ramp of the cyclonic chamber.
Another embodiment of the vortex particle separator can be constructed with all of the variations listed for the first embodiment, and which also includes a second stage for separation of particles separate from the first stage. The second stage could be divided from the first stage either by a partition which separates the two stages vertically from each other, or by a partition which separates the two stages horizontally from each other. Particle separation is more efficient when larger particles are removed first, and smaller particles are removed later. This is because the bouncing of the larger particles introduces turbulence into the airflow, and may disturb the path of the smaller particles. The multiple stages can also be used to sort particles by size in some applications.
A third embodiment of the vortex particle separator is a unit with three stages. This embodiment can have all of the variations noted for the previous two embodiments, and further includes three separate chambers for collection of particles of different sizes. These three chambers can be divided vertically from each other or horizontally.
Still other objects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description wherein I have shown and described only the preferred embodiment of the invention, simply by way of illustration of the best mode contemplated by carrying out my invention. As will be realized, the invention is capable of modification in various obvious respects all without departing from the invention. Accordingly, the drawings and description of the preferred embodiments are to be regarded as illustrative in nature, and not as restrictive.